Betow Ch., Calgüner M.

In chronic otitis media and postoperative radical cavities tympano-ossicular homograft en bloc is the best and most efficient material for the restoration of the destroyed anatomy and physiology of the middle ear.
In this article we presented our special method of preparation and conservation of the homograft transplant in detail. Also the importance in selecting the right cadavers is commented upon.
The efficient transmission of sound energy from the tympanic membrane to the fluids of the inner ear is essential for good hearing. In the normal middle ear this is accomplished by a balanced system through the ossicle. For transmission of sound waves from a large membrane to a small piston, homograft is the best and most efficient material to restore the destroyed anatomy and physiology of the middle ear.
It is not too easy to obtain a suitable homograft, therefore we developed a special method for the dissection and preparation. The temporal bone is removed from selected cadavers. It is cut in such a way with a saw that afterwards the removal of the meatal flap, the tympanic membrane and the ossicular chain is facilitated.
To explain further, the temporal bone is cut in such a way, that a square is formed (fig. 1). The incision runs laterally directly on the borderline between the cartilaginous and osseous parts of the auditory canal (fig. 2), medially through the cochlea behind the foot-plate (fig. 3), anteriorly along the wall of the temporo-mandibular joint (fig. 4), posteriorly through the aditus ad antrum next to the ossicular chain (fig. 5), inferiorly along the lower part of the auditory canal wall and superiorly through the processus mastoideus and continued to the tegmen tympani. Now, using a microscope, the foot-plate of the stapes is dissected from the oval window, than the osseous labyrint and tegmen tympani are removed easily (fig. 6, 7). After the separation of the ligaments of the ossicular chain, tensor tympani and stapedial tendons, the anulus fibrosus is carefilly dissected from its groove. Also the chorda tympani is separated. At the end, the membrane of the auditory canal is removed so that the whole middle ear can be taken out. The graft must be cleaned off any bone debris.
It is conserved in a Cialit solution 1 : 5000. The homograft should stay in this solution for at least one week. It can stay in it for up to one year, provided that the solution is changed several times.
According to our 18 years of experience, we are of the opinion that the method described above is the most suitable in preparing the tympano-ossicular homograft en bloc